Added support to stream backchannel to a command (outputbc)

pkg/outputbc/client.go

@@ -0,0 +1,56 @@
+package outputbc
+
+import (
+	"io"
+	"net"
+	"os/exec"
+	"sync"
+
+	"github.com/AlexxIT/go2rtc/pkg/core"
+)
+
+type Client struct {
+	medias  []*core.Media
+	sender  *core.Sender
+	conn    net.Conn
+	send    int
+	cmd     exec.Cmd
+	pipe    io.WriteCloser
+	command []string
+}
+
+var lock = &sync.Mutex{}
+var singleInstance *Client
+
+func NewClient(command []string) (*Client, error) {
+	return &Client{command: command}, nil
+}
+
+func (c *Client) Dial() {
+	media := &core.Media{
+		Kind:      core.KindAudio,
+		Direction: core.DirectionSendonly,
+		Codecs: []*core.Codec{
+			{Name: core.CodecPCMA, ClockRate: 8000},
+		},
+	}
+
+	c.medias = append(c.medias, media)
+	if c.pipe == nil {
+		cmdName := c.command[0]
+		args := c.command[1:]
+		c.cmd = *exec.Command(cmdName, args...)
+		c.pipe, _ = c.cmd.StdinPipe()
+	}
+}
+
+func (c *Client) Open() (err error) {
+	c.cmd.Run()
+	return
+}
+
+func (c *Client) Close() (err error) {
+	c.pipe.Close()
+	c.cmd.Process.Kill()
+	return
+}